Hollow Element Repair Compound Pinhole Reduction

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Solution Overview

Problem

The existing curable body repair compounds often result in pinholes due to trapped air during mixing and spreading, which are difficult to eliminate and require multiple layers of filler and primer, leading to increased time and expense in the repair process.

Innovation Solution

A curable body repair material with a controlled diameter distribution of hollow elements, specifically glass bubbles, is used, where less than 1% of the hollow elements have a diameter greater than 75 micrometers, and the material is formulated to be friable for easy abrading, reducing pinholes and improving the repair process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional body repair compound is mixed and spread using traditional methods, then the repair material can be applied to fill damaged areas, but pinholes are created due to trapped air

Engineering Contradiction:
Improveease of applicationVSAvoidsurface smoothness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the physical parameters of the hollow elements by strictly controlling their diameter distribution (less than 1% greater than 75 micrometers, average less than 100 micrometers). This parameter control prevents air entrapment during mixing and spreading while maintaining the lightweight and easy application properties of hollow element-filled compounds.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple layers of filler and primer are applied to fill pinholes, then the pinholes can be covered, but the repair time and expense increase

Engineering Contradiction:
Improvepinhole eliminationVSAvoidrepair time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent performs preliminary action by controlling the hollow element diameter distribution before application. This pre-preparation ensures that pinholes are minimized from the start, eliminating the need for subsequent corrective layers of filler and primer that would otherwise be required to address pinhole defects.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent converts the potential harm of hollow elements creating pinholes into a benefit by implementing strict diameter control. The controlled small diameter hollow elements provide the desired lightweight and easy application properties while minimizing air entrapment, thus converting what could be a harmful effect into a beneficial outcome.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Volume of stationary object

If hollow elements with larger diameters are used, then the repair compound provides better filling capability, but pinholes increase due to trapped air

Engineering Contradiction:
Improvefilling volumeVSAvoidpinhole formation
Core Design Contradiction:
Volume of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by establishing specific diameter limits for hollow elements (average less than 100 micrometers, less than 1% greater than 75 micrometers). This parameter optimization achieves the right balance: hollow elements are large enough to provide good filling capability and lightweight properties, but small enough to minimize air entrapment and pinhole formation during application.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2137259B1Hollow element filled curable body repair compounds
Publication Date: 2014.01.29 3M INNOVATIVE PROPERTIES CO

AI summary

A curable body repair material is described. The curable body repair material includes a curable polymeric resin, and a plurality of hollow elements. The curable body repair includes less than 3% by number of hollow elements having a diameter greater than 100 micrometers. Method of making and using the same are also described.